Senate Minority Leader Mitch McConnell of Ky., and GOP lawmakers speak to reporters on Capitol Hill in Washington, Tuesday, June 3, 2014, following a Republican caucus meeting. The Republicans disparaged the Obama administrationâ€™s decision to swap Army Sgt. Bowe Bergdahl, the only American soldier held captive in Afghanistan, in exchange for high-level Taliban militants detained at Guantanamo Bay. Sen. John Thune, R-S.D., the Senate Republican Conference chairman, listens at rear. (AP Photo/J. Scott Applewhite)

U.S. President Barack Obama answers a question during a joint news conference with Poland’s President Bronislaw Komorowski at Belweder Palace in Warsaw, Poland, Tuesday, June 3, 2014. (AP Photo/Charles Dharapak)

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WASHINGTON (AP) â€” The nation’s top military officer said Tuesday the Army could still throw the book at Sgt. Bowe Bergdahl, the young soldier who walked away from his unit in the mountains of eastern Afghanistan and into five years of captivity by the Taliban.

Charges are still a possibility, Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, told The Associated Press as criticism mounted in Congress about releasing five high-level Taliban detainees in exchange for Bergdahl. The Army might still pursue an investigation, Dempsey said, and those results could conceivably lead to desertion or other charges.

Congress began holding hearings and briefings into the deal that swapped Bergdahl for Taliban officials who had been held at Guantanamo Bay, Cuba, and several lawmakers said that President Barack Obama didn’t notify them as a law governing the release of Guantanamo detainees requires. White House staff members called key members of Congress to apologize, but that didn’t resolve the issue.

Since Dempsey issued a statement Saturday welcoming Bergdahl home, troops who served with the soldier have expressed anger and resentment that his freedom â€” from a captivity that they say he brought upon himself â€” may have cost comrades’ lives. Troops sat in stony silence at Bagram Air Field when Defense Secretary Chuck Hagel announced Bergdahl’s release over the weekend.

“Today we have back in our ranks the only remaining captured soldier from our conflicts in Iraq and Afghanistan. Welcome home, Sgt. Bowe Bergdahl,” Dempsey said on Saturday.

However, Dempsey called the AP on Tuesday to note that charges were still a possibility, and he focused his thanks on the service members who searched fruitlessly for Bergdahl after he walked away, unarmed, on June 30, 2009.

“This was the last, best opportunity to free a United States soldier in captivity,” Dempsey said. “My first instinct was gratitude for those who had searched for so long, and at risk for themselves. … Done their duty in order to bring back a missing solider. For me, it was about living up to our ethos, which is to leave no soldier behind. And on that basis I was relieved to get Sgt. Bowe Bergdahl back in the ranks, and very happy for the men and women who had sacrificed to do so.”

Dempsey said Bergdahl’s next promotion to staff sergeant, which was to happen soon, is no longer automatic because the soldier is no longer missing in action and job performance is now taken into account.

Dempsey said he does not want to prejudge the outcome of any investigation or influence other commanders’ decisions. But he noted that U.S. military leaders “have been accused of looking away from misconduct” and said no one should assume they would do so in this case.

Army Chief of Staff Gen. John McHugh later said that after Bergdahl recovers physically and is “reintegrated,” the Army would “review the circumstances” of his case.

Some former soldiers who served with him were already passing judgment.

Joshua Cornelison, who was a medic in Bergdahl’s platoon said he believes Bergdahl should be held accountable for walking away.

“After he actually left, the following morning we realized we have Bergdahl’s weapon, we have Bergdahl’s body armor, we have Bergdahl’s sensitive equipment (but) we don’t have Bowe Bergdahl,” Cornelison said from Sacramento, California. At that point, Cornelison said, it occurred to him that Bergdahl was “that one guy that wanted to disappear, and now he’s gotten his wish.”

Evan Buetow, who was a sergeant in Bergdahl’s platoon, said from Maple Valley, Washington, that Bergdahl should face trial for desertion, but he also said it was less clear that he should be blamed for the deaths of all soldiers killed during months of trying to find him. Buetow said he knew of at least one death on an intelligence-directed infantry patrol to a village in search of Bergdahl.

“Those soldiers who died on those missions, they would not have been where they were … if Bergdahl had never walked away,” he said. “At the same time I do believe it is somewhat unfair for people to say, ‘It is Bergdahl’s fault that these people are dead.’ I think that’s a little harsh.”

The White House took a fourth straight day of heat for not giving Congress the required 30 days notice of a detainee release. Obama had issued a statement when he signed the law containing that requirement giving himself a loophole for certain circumstances under the executive powers clause of the Constitution.

Obama, at a news conference in Poland, defended the decision to move quickly on the exchange, saying without offering details that U.S. officials were concerned about Bergdahl’s health. Bergdahl was reported to be in stable condition at a military hospital in Germany

“We had the cooperation of the Qataris to execute an exchange, and we seized that opportunity,” Obama said. He said the process